Numerical simulations of circumstellar disk convection

Three-dimensional, fully compressible hydrodynamic simulations of thermal convection in an idealized circumstellar disk environment have been performed, featuring a linear vertical gravity, Keplerian rotation, and an imposed internal heat source. The simulations use an unrealistically low Reynolds number in order to resolve all relevant scales of motion. The rapid rotational shear is found to remove all azimuthal variations. The resulting two-dimensional structure causes the large scales to extract kinetic energy from small scales and causes angular momentum to flow radially inward, opposite to standard convective disk models. These results imply that one cannot have quasi-steady, self-sustaining disk convection. More realistic simulations at much higher Reynolds numbers are needed to confirm these results.